Devices including a plurality of reception circuits are developed today as television receivers and recording devices that include reception circuits which receive television broadcasting. For example, television receivers including a plurality of reception circuits can concurrently display reception images of a plurality of channels on the display screen. Meanwhile, recording devices including a plurality of reception circuits can concurrently record broadcasting signals of a plurality of channels.
FIG. 8 is a diagram illustrating an example of a conventional device including a plurality of reception circuits.
Signals received by an antenna 1 are supplied to a first tuner unit 2 and a second tuner unit 3. The first and second tuner units 2 and 3 individually include reception circuits 2a and 3a, respectively. Each of the reception circuits 2a and 3a receives a broadcasting signal of a specific channel (frequency). A channel received by each of the reception circuits 2a and 3a is decided, for example, on the basis of an instruction from a control unit in the device which is not illustrated.
Each of the reception circuits 2a and 3a acquires a baseband signal or an intermediate frequency signal converted from a broadcasting signal. To acquire such a baseband signal or intermediate frequency signal, a frequency signal (locally generated signal) is necessary which is mixed with a reception signal by a mixer (not illustrated) in the reception circuits 2a and 3a. A locally generated frequency signal that is mixed with a reception signal by this mixer is obtained by a phase locked loop (PLL) circuit multiplying reference frequency signals generated by oscillation circuits 2d and 3d built in the tuner units 2 and 3, respectively. The oscillation circuits 2d and 3d use crystal oscillators 2c and 3c to acquire reference frequency signals, the crystal oscillators 2c and 3c being connected to the oscillation circuits 2d and 3d, respectively.
Each of the reception circuits 2a and 3a then performs a demodulation process on a baseband signal or an intermediate frequency signal. An image signal and an audio signal obtained through this demodulation process are acquired by output terminals 2b and 3b of the reception circuits 2a and 3a. 
Patent Literature 1 describes a technique of supplying oscillation signals of a single reference signal oscillation circuit to a plurality of PLL circuits via a buffer amplifier.